1. Field of the Invention
The present invention generally relates to a processor system and a power saving method thereof, and more particularly, to a multi-processor system and a dynamic power saving method thereof.
2. Description of Related Art
A multi-processor system is composed of a general processor and one or multiple processors with special calculation capabilities. The multi-processor system adopts the concept of resource sharing to reduce the hardware cost thereof, wherein the most commonly shared resource is the storage. A storage can be used for storing any data, such as signals for indicating communication statuses between the processors and data to be simultaneously accessed by multiple processors.
Along with the widespread of multi-processor systems, many embedded devices in the market, such as desktop computers, notebook computers, cell phones, or personal digital assistants (PDAs), adopt such structures. By integrating the calculation characteristics of different processors, a multi-processor system can achieve a better performance and the efficiency thereof is higher than that of a system using a single high-speed processor.
Due to different hardware structures and different implementations of lower-level calculation units between processors, heterogeneous processors provide different execution time and power consumption when they are used to perform the same task. Thus, presently, the development of a multi-processor system is usually focused on the execution time and power consumption regarding a specific task, and task scheduling in the operating system is adjusted according to the execution outcome, so as to reduce the power consumption and improve the performance of the system. However, how to effectively integrate different characteristics of hardware structures of different processors and accordingly reduce the power consumption of the entire system is still a major subject in the industry.